One-terminal reactive organopolysiloxane having a polyalkyleneoxide group at the omega-terminal and a method for the preparation thereof

ABSTRACT

The present invention relates to a one-terminal reactive organopolysiloxane further having a hydrophilic polyalkyleneoxide group at the omega-terminal and a method for its production. Thus, the present invention provides a one-terminal reactive organopolysiloxane which is characterized by having a polyalkyleneoxide at the omega-terminal, and composed of blocks arranged in the following order: A-B—C—Y wherein A is a monovalent polyalkyleneoxide group having an alkoxy group at a terminal, B is a substituted or unsubstituted divalent alkylene group, C is a divalent polysiloxane group, Y is a monovalent group selected from the group consisting of an alkyl group having a reactive group, a hydrogen atom, a styryl group and a trialkoxysiloxy group, and provides a method for the preparation thereof.

CROSS REFERENCE

This application claims the benefits of Japanese Patent Application No.2009-221036 filed on Sep. 25, 2009, the contents of which are hereinincorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a one-terminal reactiveorganopolysiloxane further having a hydrophilic polyalkyleneoxide groupat the omega-terminal and a method for its production.

BACKGROUND OF THE INVENTION

It is known that an organopolysiloxane having a (meth)acryl group at oneterminal is synthesized by ring-opening polymerization ofhexamethylcyclotrisiloxane. For example, Japanese Patent ApplicationLaid-Open No. Sho-59-78236 describes a method for the synthesis of anorganopolysiloxane having a (meth)acryl group at one terminal bysubjecting hexamethylcyclotrisiloxane to ring-opening polymerization,wherein lithium trimethylsilanolate is used as a polymerizationinitiator, and terminating the polymerization by 3-(2-methacryloxyethoxy)propyl dimethyl chlorosilane.

Further, Japanese Patent Application Laid-Open No. Hei-7-224168describes a method for the synthesis of organopolysiloxane having a(meth)acryl group at one terminal by subjectinghexamethylcyclotrisiloxane to ring-opening polymerization in thepresence of pentacoordinate silicon catalyst, wherein trimethylsilanolor 3-methacryloxypropyl dimethylsilanol is used as a polymerizationinitiator, and terminating each polymerization by 3-methacryloxypropyldimethylchlorosilane or trimethylchlorosilane.

However, these one-terminal reactive organopolysiloxanes are siloxanepolymers consisting of hydrophobic segments. There are few examples fora one-terminal reactive organopolysiloxane having a hydrophilic group(Japanese Patent Application Laid-Open No.2008-274278).

Polyoxyalkylene compounds having a hydrolyzable silyl group, which isreactive, at a terminal is described in Japanese Patent Publication No.Sho-59-25808 and Japanese Patent Publication No. Sho-61-29379, and areused as a hydrophilic silane coupling agent. However, thesepolyoxyalkylene compounds do not have a siloxane chain.

An organopolysiloxane having a hydrophilic group is a block copolymercomposed of hydrophilic segments and hydrophobic segments. Thehydrophilic segments associate with each other, and the hydrophobicsegments associate with each other, resulting in microphase separation.Taking advantage of such a phenominon, this polysiloxane is used incosmetics and various paints, but requires further improvements, such asan introduction of more-reactive group for applications which requiredurability.

Japanese Patent Application Laid-Open No. 2001-55446 and Japanese PatentApplication Laid-Open No. 2008-202060 describe one-terminal reactivepolysiloxanes having a hydrophilic group. However, in these one-terminalreactive polysiloxanes, the hydrophilic group is located between theblock having a reactive group and the polysiloxane block. Therefore, ina case where the polysiloxane is used in paints, such a problem occursthat the hydrophilic group is covered with the siloxane segment, whichprevents the microphase separation from occurring on a surface of acoating.

Patent Literature 1: Japanese Patent Application Laid-Open No.Sho-59-78236

Patent Literature 2: Japanese Patent Application Laid-Open No.Hei-7-224168

Patent Literature 3: Japanese Patent Application Laid-Open No.2008-274278

Patent Literature 4: Japanese Patent Publication No. Sho-59-25808

Patent Literature 5: Japanese Patent Publication No. Sho-61-29379

Patent Literature 6: Japanese Patent Application Laid-Open No.2001-55446

Patent Literature 7: Japanese Patent Application Laid-Open No.2008-202060

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

To solve the afore-mentioned problem, the present inventors have maderesearch to synthesize a reactive polyorganosiloxane having ahydrophilic group at an omega-terminal. However, the functionalizationof one terminal of the reactive polysiloxane is difficult and,therefore, a method for the synthesis of a reactive polyorganosiloxanefurther having a hydrophilic group at an omega-terminal has not yet beenreported.

Means to Solve the Problem

The inventor has found that a one-terminal reactive organopolysiloxanefurther having a polyalkyleneoxide at an omega-terminal can be obtainedby subjecting hexamethylcyclotrisiloxane to ring-opening polymerization,wherein a silanol compound having a hydrophilic polyalkyleneoxide at theomega-terminal is used as a polymerization initiator, to synthesize analpha-terminal silanol-modified organopolysiloxane, which is thenreacted with a specific compound.

Thus, the present invention provides a one-terminal reactiveorganopolysiloxane having a polyalkyleneoxide at an omega-terminal,composed of blocks arranged in the following order:A-B—C—Y

wherein A is a monovalent polyalkyleneoxide group having an alkoxy groupat a terminal, B is a substituted or unsubstituted divalent alkylenegroup, C is a divalent polysiloxane group, Y is a monovalent groupselected from the group consisting of an alkyl group having a reactivegroup, a hydrogen atom, a styryl group and a trialkoxysiloxy group, andprovides a method for the preparation thereof.

Effects of the Invention

The one-terminal reactive organopolysiloxane of the present inventionfurther has a hydrophilic polyalkyleneoxide at the omega-terminal.Therefore, when the alpha-terminal of the organopolysiloxane issubjected to a reaction to form a silicone-grafted polymer, a coatinghaving a good surface property can be provided.

BRIEF DESCRIPTION ON THE DRAWING

FIG. 1 is a chart of ¹H-NMR spectra of the compound prepared in Example1.

BEST MODES OF THE INVENTION

The present invention is a one-terminal reactive organopolysiloxanewhich is characterized by having a polyalkyleneoxide at theomega-terminal, and composed of blocks arranged in the following order:A-B—C—Y

wherein A is a monovalent polyalkyleneoxide group having an alkoxy groupat a terminal, B is a substituted or unsubstituted divalent alkylenegroup, C is a divalent polysiloxane group, Y is a monovalent groupselected from the group consisting of an alkyl group having a reactivegroup, a hydrogen atom, a styryl group and a trialkoxysiloxy group.

An example of the organopolysiloxane composed of the above-mentionedblocks is an organopolysiloxane represented by the following formula(1).

In formula (1), R¹ is an alkyl group having 1 to 10 carbon atoms, R² isa hydrogen atom or methyl group, R³ is an alkylene group having 1 to 10carbon atoms, R⁴ is, independently of each other, a group having 1 to 10carbon atoms selected from the group consisting of an alkyl group, analkenyl group and an aryl group, m is an integer of from 1 to 100,preferably from 5 to 50, more preferably from 10 to 30, and n is aninteger of from 5 to 300, preferably from 10 to 150, more preferablyfrom 20 to 50.

In formula (1), Y is a monovalent group selected from the groupconsisting of an alkyl group having a reactive group, a hydrogen atom, astyryl group and a trialkoxy siloxy group. Examples of the reactivegroup include a (meth)acryl group, a (meth)acrylamide group, an aminogroup, an epoxy group and an acid anhydride group. The alkyl group andthe aloxy group preferably have 1 to 10 carbon atoms. Among these,preferred are an alkyl group which has a (meth)acryl group or a(meth)acrylamide group, and a trialkoxysiloxy group.

Examples of Y include those represented by the following formulas.

The present invention also provides a method suitable for preparing theafore-mentioned one-terminal reactive organopolysiloxane having apolyalkyleneoxide at the omega-terminal. In this method, apolyalkyleneoxide-modified silanol represented by the following formula(2):

wherein R¹, R², R³ , R⁴ and m are as defined above, is reacted withhexamethylcyclotrisiloxane to prepare an intermediate represented by thefollowing formula (3)

wherein R¹, R², R³, R⁴, m and n are as defined above.

Next, the afore-mentioned intermediate represented by the formula (3) isreacted with an organosilicon compound which is reactive with a silanol,whereby the organopolysiloxane of the present invention can be obtained.Examples of the organosilicon compound include those represented by anyone of the following general formulas (4) to (8):

wherein R⁴ is, independently of each other, a group having 1 to 10carbon atoms selected from the group consisting of an alkyl group, analkenyl group and an aryl group, R⁵ is an alkylene group having 1 to 10carbon atoms, R⁶ is a hydrogen atom or a methyl group and R⁷ is a methylgroup or an ethyl group.

More specific examples of the organosilicon compound include thoserepresented by the following formulas.

The present organopolysiloxane can also be prepared by reacting theafore-mentioned intermediate represented by the formula (3) withdimethylchlorosilane to prepare an organopolysiloxane having a terminalSiH group, which is then subjected to an additional reaction with avinyl group-containing compound which is represented by the followingformula (9), (10) or (11):

wherein R⁵ is as defined above.

The pathway for the afore-mentioned synthesis will be described below inmore detail.

(i) Synthesis of the polyalkyleneoxide-Modified silanol

The afore-mentioned polyalkyleneoxide-modified silanol represented bythe general formula (2) can be obtained by subjecting the terminal vinylgroup of a polyoxyalkylene represented by the following formula to anadditional reaction, i.e. hydrosilylation, with one Si—H group oftetramethyldisiloxane, and subsequently converting the remaining Si—Hgroup of tetramethyldisiloxane into a silonol group,

wherein R¹ is an alkyl group having 1 to 10 carbon atoms, R² is ahydrogen atom or a methyl group, m is an integer of from 1 to 100,preferably from 5 to 50, more preferably from 10 to 30.

The polyoxyalkylene and tetramethyldisiloxane are fed in a ratio of from6 to 40 equivalents, particularly 10 to 30 equivalents, of the Si—Hgroup of tetramethyldisiloxane, per equivalent of the vinyl group of thepolyoxyalkylene. In this additional reaction, obtained are a compoundwhere the polyoxyalkylene is added to one terminal oftetramethyldisiloxane and a compound where the polyoxyalkylene is addedto both terminal of the tetramethyldisiloxane. However, the siloxanecompound having the Si—H group at the one terminal can be prepared inthe ratio of 95% or more, using a largely excess equivalent amount oftetramethyldisiloxane, relative to the equivalent amount of thepolyoxyalkylene. The additional reaction may be carried out with nosolvent or in the presence of a solvent such as an ether solvent, anaromatic solvent and an aliphatic hydrocarbon solvent. Among these,toluene is preferred. In the present invention, the compound where thepolyoxyalkylene is added to both terminal of the tetramethyldisiloxanemay be use without being sapareted in the subsequent reaction.

A catalyst may be used in the additional reaction. Any known catalystcan be used, such as, for example, a platinum catalyst or a palladiumcatalyst, but is not limited to these. Particularly, preffered is aneutral platinum catalyst, such as, a zero-valent platinum catalystwhere an unsaturated compound is coordinated. More specifically,hexachloroplatinic (IV) acid hexahydrate, a platinum carbonyl vinylmethyl complex, a platinum-divinyltetramethyldisiloxane complex, aplatinum-cyclovinylmethylsiloxane complex, aplatinum-octylaldehyde/octanol complex or platinum supported onactivated coal may be used. Among these, atetramethyldivinyldisiloxane-coordinated, zero-valent platinum catalystis preffered. The catalyst is preferably used in an amount of from 1 to50 ppm, more preferably from 3 to 20 ppm, of platinum metal relative tothe amount of the polyoxyalkylene.

The additional reaction is carried out preferably at a temperature of 30to 150 degrees C., particularly 80 to 120 degrees C., for 1 to 5 hours.When the reaction is carried out in a closed system such as anautoclave, the reaction time can be reduced, and the conversion in thehydrosilylation can be increased.

Next, the siloxane compound having an Si—H group at one terminal issubjected to dehydrogenation in the presence of water, whereby the Si—Hgroup is converted into a silanol group. The water used in the reactionis used in a molar amount at least equal to, preferably 3 to 10 times,relative to the molar amount of the Si—H group. A catalyst such as aplatinum catalyst, a palladium catalyst or a hydroxylamine catalyst, forexample, a palladium carbon, may be used. The catalyst is used in suchan amount of that the amount of the metal is from 40 to 200 ppm,preferably from 60 to 150 ppm, relative to the amount of thepolyoxyalkylene having the Si—H bond at one terminal. Further, a solventmay be used in this silanol forming reaction, if needed. Preferred is awater-soluble solvent such as a ketone, an alcohol or an ether. Thesilanol forming reaction may be carried out at a temperature of 30 to150 degrees C., preferably 50 to 100 degrees C.

(ii) Synthesis of the Intermediate

The intermediate represented by the formula (3) can be obtained bysubjecting hexametylcyclotrisiloxane to ring-opening polymerization ofthe afore-mentioned silanol compound. Hexametylcyclotrisiloxane is usedin an amount of 1 to 100 equivalents, preferably 4 to 50 equivalents,relative to one equivalent of the hydroxyl group of the silanolcompound. This ring-opening polymerization is carried out in thepresence of a polymerization catalyst. Any known polymerization catalystcan be used. Preferred is a pentacoordinate silicon catalyst representedby the following formula (12), as described in Japanese PatentPublication No. Sho-45-1070:

wherein R⁵ is a substituted or unsubstituted monovalent hydrocarbongroup, and M is Li, Na, K, NH₄ or C₆H₅CH₂N(CH₃)₃. R⁵ is preferably amonovalent hydrocarbon group having 1 to 12 carbon atoms.

Examples of the pentacoordinate silicon catalyst include thoserepresented by the following formulas.

Among these, a pentacoordinate silicon catalyst which has an alkalimetal as a counterion is preferred, because the synthesis is easy, thestability over time is good and the polysiloxane obtained in thepolymerization is better monodisperse. The pentacoordinate siliconcatalyst represented by the following formula is particularly preferred.

The pentacoordinate silicon catalyst used in the reaction is usedpreferably in an amount of 100 to 1000 ppm, more preferably 200 to 500ppm, relative to the amount of hexametylcyclotrisiloxane.

The ring-opening polymerization may be carried out in the presence of asolvent. A polar solvent or a polar solvent which does not contain anactive hydrogen can be used as the reaction solvent, such as, forinstance, acetonitrile, tetrahydrofuran, 1,4-dioxane, methylethylketone,methylisobutylketone, dimethyl sulfoxide, dimethylformamide, hexane,toluene and xylene. Among these, acetonitrile is preferred. The reactionsolvent is preferably dehydrated by a drying agent such as molecularsieves.

Reaction conditions for the ring-opening polymerization may properly beselected. A reaction temperature may be 50 to 100 degree C., preferably60 to 80 degree C., and a reaction time is 1 to 20 hours. According tothe afore-mentioned reaction, the intermediate having apolyalkyleneoxide at the omega-terminal and a silanol at thealpha-terminal can be obtained.

(iii) Synthesis of the One-Terminal Reactive organopolysiloxane

The intermediate obtained in the afore-mentioned reaction is reactedwith an organosilicon compound which is reactive with a silanol. As theorganosilicon compound, the organochlorosilan represented by theafore-mentioned formulas (4) to (7), or ketene silyl acetal representedby the afore-mentioned formula (8) may be used.

The organochlorosilan represented by the afore-mentioned formulas (4) to(7) may be used in an amount of 1.0 to 1.5 moles, preferably 1.0 to 1.2moles, relative to one mole of the intermediate represented by theafore-mentioned formula (3).

The additional reaction with the organochlorosilan is carried out bydropping the organochlorosilan directly into the reaction solutionobtained after the preparation of the intermediate. This additionalreaction is carried out preferably in the presence of a hydrochloricacid scavenger. Examples of the hydrochloric acid scavenger includevarious kinds of amine, for instance, pyridine and triethylamine, withtriethylamine being preferred. In a case where organochlorosilan has a(meth)acryl group, dibutyl hydroxytoluene (BHT) is preferably added toprevent polymerization of the (meth)acryl group. The reaction conditionsare preferably such a reaction temperature of 20 to 100 degrees C.,particularly 50 to 80 degrees C., and a reaction time of 1 to 10 hours.After the end of the reaction, methanol is added to deactivate theremaining chlorosilan, and reaction solvent is removed by stripping at a100 degrees C./10 mmHg. According to this process, the one-terminalreactive organopolysiloxane having the polyalkyleneoxide at theomega-terminal can be obtained.

The ketene silyl acetal represented by the afore-mentioned formula (8)may be used in an amount of 1.0 to 3.0 moles, preferably 1.5 to 2.0moles, relative to one mole of the intermediate represented by theafore-mentioned formula (3).

The additional reaction using the ketene silyl acetal is carried out bydropping the ketene silyl acetal directly into the reaction solutionobtained after the preparation of the intermediate. Reaction conditionsare preferably a reaction temperature of 50 to 80 degrees C.,particularly 60 to 70 degrees C., and a reaction time of 1 to 10 hours.After the end of the reaction, methanol is added to deactivate thecatalyst, and the reaction solvent is removed by stripping at a 100degrees C./10 mmHg. According to this process, the one-terminal reactiveorganopolysiloxane having the polyalkyleneoxide at the omega-terminalcan be obtained.

Alternatively, the present organopolysiloxane can be obtained asfollows: an organopolysiloxane having a terminal Si—H group is obtainedby reacting the intermediate represented by the afore-mentioned formula(3) with dimethylchlorosilan according to the afore-mentioned reactionwith an organochlorosilan, and then reacted with a vinylgroup-containing compound represented by the afore-mentioned formula(9), (10) or (11). Any known method can be used for the additionalreaction between the Si—H group and the vinyl group, and is not limited.The vinyl group-containing compound is used in an amount of 1 to 3equivalents, relative to one equivalent of the Si—H group of theorganopolysiloxane. Any unreacted vinyl group-containing compound can beremoved at the same time as when the solvent is removed after the end ofthe reaction. The reaction is preferably carried out at a temperature of30 to 150 degrees C., preferably 80 to 120 degrees C., for 1 to 5 hours.

The one-terminal reactive organopolysiloxane having a (meth)acryl group,a (meth)acrylamide group or a styryl group at the alpha-terminal cancopolymerize with a vinyl monomer to provide a graft copolymer which hasgood water repellency, releasing property, lubricating property, weatherresistance and gas permeability. Further, the one-terminal reactiveorganopolysiloxane having an alkoxysilyl group, a hydrosilyl group, anepoxy group, an amino group or an acid anhydride group at thealpha-terminal can be used as a surface treatment agent such as a silancoupling agent and a hard coat agent.

EXAMPLES

The present invention will be explained more specifically with referenceto the following Examples. However, the present invention shall not belimited thereto.

The measuring apparatus used in the Examples are as follows.

Infrared spectrophotometer: SPECTRUM 2000, produced by PERKIN ELMER Co.,Ltd

GPC: HLC-8220, produced by TOSO Co., Ltd

NMR: AVANCE 111-400, produced by Buruker Co., Ltd, ¹H-NMR

Example 1

(i) Synthesis of a polyalkyleneoxide-Modified silanol

To a three-litter flask equipped with a stirrer, a thermometer, a refluxcondenser, and a dropping funnel were added 400 g of ω-methoxypolyethyleneglycol monoallylether (Mw 550), 974 g of1,1,3,3-tetramethyldisiloxane (molar ratio of Si—H group/Si-Vi group,20), 500 g of a toluene and 0.48 g of a toluene solution of atetramethyldivinyldisiloxane-coordinated zero-valent platinum catalystcontaining 0.5% by weight of platinum metal (6 ppm of platinum metal),and heated at 70 degrees C. for 5 hours to react. The reaction mixturewas subjected to stripping to remove volatiles to obtain 484 g of alight brown viscous liquid product. The absorption (2,125cm⁻¹) by theSi—H bond of the product was confirmed by an infrared spectrophotometer.The average molecular weight was 690, as determined by the amount of theproduced hydrogen gas.

To a five-hundred milliliter flask equipped with a thermometer, atubular condenser and a stirrer were added 300 g of the afore-mentionedproduct, 150 g of tetrahydrofuran and 1.5 g of palladium carboncontaining 2.0% by weight of palladium metal (100 ppm of palladiummetal), to which 15 g of water was added dropwise in an ice bath, andheated to 70 degrees C. for hours to react. Then, the reaction mixturewas subjected to stripping to remove the volatiles. After removal of thepalladium carbon by filtration, 286 g of a light brown viscous liquidproduct was obtained.

The afore-mentioned product was subjected to infrared spectrophotometry.The absorption by the Si—H bond (2,125 cm⁻¹) was not seen and absorptionby the Si—OH bond (3,400 cm⁻¹) was confirmed. The conversion wasapproximately 100%, as determined by calculating the amount of theremaining Si—H bond, based on the amount of the hydrogen gas produced. Aweight-average molecular weight of the product, reduced to polystyrene,was approximately 700, as determined by gel permeation chromatography(GPC). Therefore, the product obtained was the silanol compoundrepresented by the following formula (13).

(ii) Synthesis of an Intermediate

To a five-hundred milliliter flask equipped with a thermometer, afurther condenser and a stirrer were added 140 g of the silanol compoundrepresented by afore-mentioned formula (13), 444 g ofhexamethylcyclotrisiloxane and 196 g of dehydrated acetonitrile, andheated to 50 degrees C. in an oil bath to prepare a homogenous solution.To the reaction mixture, 0.156 g of a pentacoordinate silicon catalystrepresented by the following formula (14) was added, and stirred at 60degrees C. for 3 hours to allow polymerlyzation.

(iii) Synthesis of a One-Terminal Reactive organopolysiloxane

Then, 88.8 g of ketene silyl acetal (0.43 mol) represented by thefollowing formula (15) was added dropwise to the reaction mixture at 10degrees C., stirred at 70 degrees C. for 3 hours to react. Then, 84 g ofmethanol was added to deactivate the catalyst. The mixture was subjectedto stripping at 100 degrees C./10 mm Hg to remove the solvent and slightamounts of low volatiles, and filtrated with activated carbon to removethe polymerization catalyst to obtain a transparent, light brown oilproduct. The amount of the product was 560 g and the yield based on thesilanol compound represented by the formula (13) was 97.0%.

The product obtained was subjected to measurement of a viscosity at 25degrees C., a specific gravity, a refractive index and a weight-averagemolecular weight as determined by gel permeation chromatography.

-   -   Viscosity: 100 mm²/s    -   Specific gravity: 0.999    -   Refractive index: 1.4139    -   Weight-average molecular weight: 2900

The product obtained was analyzed by ¹H-NMR and was found to be acompound represented by the following formula (16). The ¹H-NMR spectraare shown in FIG. 1.

Example 2

The silanol compound represented by the afore-mentioned formula (13) wasprepared as in Example 1, and subjected to polymerization withhexacyclotrisiloxane. After the polymerization, 0.11 g of butylatedhydroxytoluene (BHT), 24.0 g of pyridine and 82 g of toluene were addedto the reaction mixture with stirring, and cooled in an ice bath. 45.3Grams of methacryloyl propyl dimethyl chlorosilane (0.21 mol) was addeddropwise. Then, the reaction mixture was heated at 70 degrees C. for 2hours with stirring to cap the end. 20 Grams of methanol was added todeactivate the remaining chlorosilane. Then, the reaction mixture wassubjected to stripping at 100 degrees C./10 mm Hg to remove the tolueneand slight amounts of low volatiles, and filtrated with activated carbonto remove the polymerization catalyst to obtain a transparent, lightbrown oil product. The amount of the product was 581 g and the yieldbased on the silanol compound represented by the formula (13) was 98.0%.The product obtained was found to be a compound represented by thefollowing formula (17).

INDUSTRIAL APPLICABILITY

The present one-terminal reactive organopolysiloxane can provide asilicone graft polymer with good surface properties on account of thepolyalkyleneoxide at the omega-terminal, and is useful as anintermediate to synthesize graft copolymers which are available as awater repellent agent for concrete, a protective coating against aposters, an undersea antifouling coating, a weather resistant coating,an antisticking agent for a thermal-transfer recording film, aprotective coating against water landing or snow accretion, cosmeticmaterials and contact lens materials.

The invention claimed is:
 1. A one-terminal reactive organopolysiloxanehaving a polyalkyleneoxide at an omega-terminal, composed of blocksarranged in the following order:A-B—C—Y wherein A is a monovalent polyalkyleneoxide group having analkoxy group at a terminal, B is a substituted, or unsubstituteddivalent alkylene group, C is a divalent polysiloxane group, and Y is amonovalent group selected from the group consisting of an alkyl grouphaving a reactive group selected from the group consisting of(meth)acryl groups, (meth)acrylamide groups, amino groups, epoxy groups,and acid anhydride groups, a hydrogen atom, a styryl group and atrialkoxysiloxy group.
 2. The one-terminal reactive organopolysiloxaneaccording to claim 1, wherein the organopolysiloxane is represented bythe following formula (1):

wherein R¹ is an alkyl group having 1 to 10 carbon atoms, R² is ahydrogen atom or a methyl group, R³ is an alkylene group having 1 to 10carbon atoms, R⁴ is, independently of each other, a group having 1 to 10carbon atoms selected from the group consisting of an alkyl group, analkenyl group and an aryl group, and Y is a monovalent group selectedfrom the group consisting of an alkyl group selected from the groupconsisting of (meth)acryl groups, (meth)acrylamide groups, amino groups,epoxy groups, and acid anhydride groups, a hydrogen atom, a styryl groupand a trialkoxysiloxy group, m is an integer of from 1 to 100 and n isan integer of from 5 to
 300. 3. A method for preparing the one-terminalreactive organopolysiloxane according to claim 2, wherein apolyalkyleneoxide-modified silanol represented by the following formula(2):

wherein R¹, R², R³ , R⁴, and m are as defined in claim 2, is reactedwith hexamethylcyclotrisiloxane to prepare an intermediate representedby the following formula (3):

wherein R¹, R², R³, R⁴,m, and n are as defined in claim 2, and then theintermediate is reacted with an organosilicon compound which is reactivewith a silanol.
 4. The method according to claim 3, wherein theorganosilicon compound is selected from the group consisting ofcompounds represented by any one of the following general formulas (4)to (8):

wherein R⁴ is as defined above, R⁵ is an alkylene group having 1 to 10carbon atoms, R⁶ is a hydrogen atom or a methyl group and R⁷ is a methylgroup or an ethyl group.
 5. A method for preparing the one-terminalreactive organopolysiloxane according to claim 2, wherein apolyalkyleneoxide-modified silanol represented by the following formula(2):

wherein R¹, R², R³, R⁴, and m are as defined in claim 2, is reacted withhexamethylcyclotrisiloxane to prepare an intermediate represented by thefollowing formula (3):

wherein R¹, R², R³, R⁴, m, and n are as defined in claim 2, theintermediate is reacted with dimethylchlorosilane to prepare anorganopolysiloxane having a terminal SiH group, and then theorganopolysiloxane having a terminal SiH group is subjecting to anadditional reaction with a compound represented by the following formula(9), (10) or (11):

wherein R⁵ is an alkylene group having 1 to 10 carbon atoms.
 6. Themethod according to any one of claims 3 to 5, wherein the reactionbetween the polyalkyleneoxide-modified silanol represented by saidformula (2) and hexametylcyclotrisiloxane is carried out in the presenceof a pentacoordinate silicon catalyst represented by the followingformula (12):

wherein R⁵ is a substituted or unsubstituted monovalent hydrocarbongroup, and M is Li, Na, K, NH₄ or C₆H₅CH₂N(CH₃)₃.